Nonuniversality due to inhomogeneous stress in semiconductor surface
nanopatterning by low-energy ion-beam irradiation

A Moreno-Barrado and M Castro and R Gago and L Vazquez and J Munoz-
Garcia and A Redondo-Cubero and B Galiana and C Ballesteros and R
Cuerno, PHYSICAL REVIEW B, 91, 155303 (2015).

DOI: 10.1103/PhysRevB.91.155303

A lack of universality with respect to ion species has been recently
established in nanostructuring of semiconductor surfaces by low-energy
ion-beam bombardment. This variability affects basic properties of the
pattern formation process, like the critical incidence angle for pattern
formation, and has remained unaccounted for. Here, we show that
nonuniform generation of stress across the damaged amorphous layer
induced by the irradiation is a key factor behind the range of
experimental observations, as the form of the stress field is controlled
by the ion/target combination. This effect acts in synergy with the
nontrivial evolution of the amorphous-crystalline interface. We reach
these conclusions by contrasting a multiscale theoretical approach,
which combines molecular dynamics and a continuum viscous flow model,
with experiments using Xe+ and Ar+ ions on a Si(100) target. Our general
approach can apply to a variety of semiconductor systems and conditions.